Atom interferometric-based (AI-based) devices apply the science of coherent atom-laser interactions to make sensitive and accurate measurements of the trajectories of ensembles of atoms, in order to determine acceleration. A classical analogy for the AI-based acceleration measurement is to consider measuring the trajectory of a proof mass in an accelerating reference frame. As depicted in FIG. 1 in the prior art, an atom-interferometric accelerometer essentially operates by replacing the relatively large proof mass with atoms. The atoms are situated in an entity known as an “atom cloud.” The atom cloud is released—that is, dropped or launched—and effectively becomes a reference point in space. During the atom cloud's free fall, a measuring laser such as a Raman laser is used to measure the accelerometer's motion relative to the atom cloud. The measuring laser measures the atoms' trajectory through three successive interactions with laser beams, namely φ(t1), φ(t2), and φ(t3), where the φ-values are indicative of atom cloud displacement and t1, t2, and t3 are the times at which these displacements are measured. The interactions are separated by interval TR.
An AI-based accelerometer is advantageous for a variety of reasons. First, it provides precise inertial measurements, as they are based on the interference of atom waves. Second, the device has no moving parts, except for the atoms, thereby providing the potential for low-cost, low-maintenance sensors. Third, the atom densities in the coherent atom cloud provide the potential for high signal-to-noise ratios. And fourth, the use of an atomic proof mass ensures that the material properties between sensor proof masses will be identical.
Additionally, an atom interferometric accelerometer has the potential to exhibit superior low frequency performance over conventional accelerometers, which rely on larger proof masses to provide acceleration measurements.